The Effect of Infill Walls on the Structural Identification of an Existing RC Frame Building

A large number of Reinforced Concrete (RC) frames buildings containing unreinforced masonry infill walls are commonly used in structural system around the world. Earthquakes revealed that the performance of this type of buildings can be significantly affected by infill walls according their type and distribution in plane and along the height. The paper describes the experimental and analytical modal analysis of an existing RC framed building underling the influence of infill walls and partitions. An ambient vibration test was carried out and analysed by OMA; a 3D finite element model, comprehensive of infill walls and partitions, was successfully updated manually based on the in-situ test global modes. The progressive introduction of the infill walls and partitions, with the updating of their characteristics, allowed to demonstrate their essential effect on the elastic dynamic response of the structure and the necessity of their modelling to attain a reliable structural identification and model assessment.